Means for cleaning surfaces of oil and oily deposits and for reclaiming the liquid used in cleaning



June 28, 1955 R. GRQQM 2,711,978

MEANS FOR CLEANING SURFACES OF OIL AND OILY DEPOSITS AND FOR RECLAIMINGTHE LIQUID USED IN CLEANING Filed Aug. 8, 1951 6 Sheets-Sheet 1 MIXINGmum.

Inventor,

June 28, 1955 R GROQM 2,711,978

MEANS FOR CLEANING SURFACES OF OIL AND OILY DEPOSITS AND FOR RECLAIMINGTHE LIQUID USED IN CLEANING Filed Aug. 8, 1951 6 Sheets-Sheet 2 7 5ERfGl/VALD M ERGO/1 June 28, 1955 R W GROOM MEANS FOR CLEANING SURFACESOF OIL AND OILY DEPOSITS AND FOR RECLAIMING THE LIQUID USED IN CLEANING6 Sheets Filed Aug. 8, 1951 REGINALD M Sheet 3 I nventor GPOOM AttorneyJune 28, 1955 R. w. GROOM MEANs FOR CLEANING SURFACES OF oIL AND OILYDEPOSITS AND FOR RECLAIMING THE LIQUID USED IN CLEANING 6 Sheets-Sheet 4Filed Aug. 8, 1951 REGINALD MGROOM By W Atlornev June 28, 1955 R w GRQOM2,711,978

MEANS FOR CLEAN SURFACES OF OIL AND OILY DEPOSITS AND FOR RECL ING THELIQUID USED IN CLEANING 6 Sheets-Sheet 5 Filed Aug. 8, 1951 In ventor,REG/M410 M 6/2001! Attorney June 28, 1955 w, GROOM 2,711,978

MEANS FOR CLEANING SURFACES OF OIL AND OILY DEPOSITS AND FOR RECLAIMINGTHE LIQUID USED IN CLEANING Filed Aug. 8, 1951 6 Sheets-Sheet 6 I23. /53I52 F/G. /8. 57/55 F/G. l7

/2 F/G. /9 Q #26 25 NALD M nventor I25 By Attorney United States PatentMEANS FOR CLEANING SURFACES OF OIL AND OlLY DEPOSITS AND FOR RECLAIMINGTHE LIQUID USED IN CLEANING Reginald William Groom, Bromley, England.

Application August 8, 1951, Serial No. 240,944

4 Claims. (Cl. 134-10) This invention relates to the removal ofdeposited matter, e. g. oil and oily deposits from the surfaces on whichsuch matter is deposited.

Hitherto the removal of oil and oily deposits from oil tanks, shipsdouble bottom tanks, and chambers such as under piston superchargers hasmainly had to be done by hand, and in view of the unpleasant andunhealthy nature of the work it has been difiicult to get workmen toundertake it. For example, in the cleaning of ships double bottom tanks,the workmen have had to bucket out the dirty oil in confined and remotespaces--work which was arduous, exhausting and dangerous to health.

Prior proposals have been made for effecting this work by mechanicalmeans, involving the projection of liquids against the surfaces to becleaned, but in such cases large volumes of liquid (6. g. of the orderof 400 gallons per minute) at high temperatures (for example over 200F.) have been required, thus demanding large and costly heat exchangers.Furthermore, such systems have relied upon high pressure impact of theliquid to erode or knock ofi the oil or other sediments from thesurfaces to be cleaned. Furthermore, the apparatus provided in suchsystems has not allowed for the cleaning of remote places or placesdiflicult of access, such as are formed by tank corners, reinforcingbeams and the like.

it is thus an object of the present invention to deal with these variousdifiiculties and to provide for a more efiicient cleaning.

A further object of the invention is to enable the liquid used for thecleaning operation to be automatically reclaimed after use andsubsequently re-employed so that only a relatively small quantity ofliquid is used.

Another object is to recover oil from the deposited matter.

To this end the present invention provides a method of removingdeposited oil and foreign matter from the walls of ships and other oiltanks and like surfaces, such method comprising the steps of projectingan aqueous detergent liquid on to the surface tobe cleaned so aspartially to emulsify and thereby remove the deposited oil; collectingand withdrawing the detergent liquid (contaminated with the removed oiland foreign matter), and separating the oil and foreign matter from thedetergent liquid; and recycling the latter for re-use in the cleaningoperation, and withdrawing the reclaimed oil and. foreign matterseparately from the separated detergent liquid.

The arrangement is such that the detergent liquid is forwarded in heatedcondition from the detergent container to a projector which directs theliquid against the surfaces to be cleaned, whereafter the liquid withentrained matter is automatically returned to the scumming' container,the entrained matter there separated out and the clean liquid passedback into the detergent container for re-cycling. Hence a comparativelysmall quantity of detergent can be used over and over again. Moreover,the invention provides for the recovery of the matter removed from thetank wall orother surface. In the case of oil tanks, the recovery of theoil in this way can repre-- sent a substantial economy.

The recirculation of the detergent liquid is effected by pump meanswhich can, if necessary, be provided as part of the cleaning equipment,or use may be made of existing pumping installations for this purpose.

The detergent used in the case of the removal of oil from the walls oftanks and the like is destined to effect a partial emulsification of theoil and thus destroy the interfacial tension between this oil and themetal of the wall,-and the detergent used will be suitably selectedaccording to the material to be dealt with.

By the term detergent liquid is meant an aqueoussolution of awater-soluble detergent compound or mixture consisting of or comprisinga wetting agent, prefer ably with one or more of the followingadditional compounds:

' Sodium sulphate.

Sodium nitrate. Sodium chloride.

The above additional compounds, or the equivalent potassium salts, canbe used with the wetting agent either 2 alone or in various admixtureswith one another in proportions varying from 0l00%, according to thespecific tively, only a small proportion of such additional 'compoundsused, e. g. up to of the wetting agent.

The wetting agents referred to are those known as water soluble surfaceactive agents and belonging to either the cationic, anionic, ornon-ionogenic class.

In a similar way, the temperature to which the deter- '1 gent liquid israised in the detergent container will depend first on the appropriatetemperature at which it' should meet theoil or the like and secondly onthe heat losses likely to be encountered in its passage fromthe.

detergent container to the point of use. It has been found that atemperature of about 160 F. in the detergent container, producing atemperature at the point of use of about 150 F. is very suitable.

Again, the pressure of the detergent liquid at the point of dischargecan also vary, but to lbs. per square inch has been found suitable.Moreover a forwarding rate for the liquid of about 4 to 8 gallons perminute has also proven satisfactory.

Various features of the invention, relating to the formation and partsof the detergent and scumming containers, and various forms ofprojector, both mechanically andmanually operable in nature, arehereinafter disclosed in the specification and claims.

The accompanying drawings illustrate forms of various parts of theinvention, and reference will now be made to these drawings.

Figure 1 is a diagrammatic illustration of a combined detergent andscumming container, in accordance with the invention, indicating thevarious connections thereof which may be used in accordance with theinvention;

Patented June 28, 1955v Figure 2 is a diagrammatic indication ofconnections to the return pump used in association with the equipment;

Figure 3 is a vertical cross section of one form of tank according tothe invention in which the detergent and scuniming containers arecombined; 7 I

Figure 4 is a plan view corresponding to Figure};

Figure 5 is a view, partly in vertical cross-section, of one form ofmechanical projector according to the invention;

Figure 6 is a view, on a smaller scale, of the pro ector showing itmounted for use inside a tank to be cleaned;

Figure 7 is a cross section on the lines VlI-V1I of Figure 5;

Figure 8 is a side elevation of a means for controlling the speed ofprojection, and for controlling the retract on, of the projectorillustrated in Figures to 7; I n

' Figure 9 is a plan view of the device illustrated in Figure 8;

Figure 10 is a section, on an enlarged scale, through the projectornozzle used with the device illustrated in Figures 5 to 7;

Figure 11 is a view, partly in section, of the nozzle unit, as seen atright angles to the aspect illustrated in Figure l0;

Figure 12 is an end view of an element seen in Fig- Figure 13 is a view,partly in section, of a manually operated form of projector which can beused in accordance with the invention;

Figure 14 is a plan view of the nozzle and nozzle control parts of theprojector illustrated in Figure 13;

"Figure 15 is a section on XV-XV, of Figure 14;

Figure 16 is a horizontal section through one of the nozzles of Figure14; I

Figure 17 is a diagrammatic indication of. a collar which is used with.the equipment according to the nvention in the particular case of thecleaning of under piston superchargers;

Figure 18 is a sectional illustration of a pro ector adapted for use inthis particular application; and

Figure 19 is an elevation, partly in section, of the collar indicated inFigure 17.

i A general diagrammatic indication of the layout of the equipmentaccording to the invention is illustrated in Figure 1 of the drawings.This indicates a main tank 1 which is divided by a partition, indicatedat 2, into two containers 3 and 4, the first of which is intended toreceive the detergent liquid returning from the cleaning operation, withthe oil and foreign matter suspended therein, and which container willhereinafter be referred to as the scuniming container. The secondcontainer 4, herein after called the detergent container, is that whichcontains the fresh or cleaned detergent liquid and from which the latterpasses to the proiector or projectors for effecting the cleaningoperation. I

In this arrangement an auxiliary tank 5 for containing the detergentliquid and intended for making up the detergent liquid in the scummingcontainer is indicated as being mounted on the top of the main tank 1straddling the partition 2.

A make-up pipe 6 controlled by valves 7 and 8 leads from the make-uptank 5 into the scumming container 3. A further make-up pipe 9, thistime controlled only by the valve 7, passes from the make-up tank 5externally of the tank 1 and is inserted at its lower end into thescumming container 3 at the position of a ball float valve therein, aswill be referred to hereinafter.

. The detergent liquid in the detergent container 4 is heated by steamwhich passes through a coil (to be hereinafter referred to) suppliedthrough a steam line 26, con trolled by a valve 11, from a steamproducer (not shown).

The heated detergent liquid passes along a line 13 from the detergentcontainer 4, being pumped in the direction of the arrow by means of asuction pump 16 to the place of use, and after use it is returned,containing entrained substances, largely deposited oil and foreignmatter in the form of solids such as oxidised oil and asphalticresiduals from the walls of the cleaned receptacle, by means of afurther pump 21 (see Figure 2) through a return line 22 controlled by agate valve 23 to the scumming conminor 3, the pipe line 22 itselfpassing through the detergent heating container 4 before discharginginto the scumrning container 3 and completing the cycle.

A branch 19 from the steam line 26, with a valve 27 therein leads to adrum or container 12 used for mixing the detergent solution. In practicea highly concentrated detergent liquid is made up in the drum 12 byfilling the latter with water, opening valve 27 to deliversteam into thedrum to raise the temperature of the water, and then adding thedetergent in solid form into the heated water in the drum 12.

Before commencement of the cleaning operation the concentrated liquidmixed in 12 is pumped into the makeup tank 5 where it is diluted to thestrength required for the cleaning operation and then discharged intothe scumming container 3 via the line 6, this procedure being re peateduntil the level of the detergent liquid has risen to the permissiblelimit in containers 3 and 4, a reserve supply being kept in tank 5 byshutting down valve 8.

Use is made of pump 16 in effecting the transfer of detergent liquidfrom drum 12 to make-up tank 5, a connection 17, with a valve 13therein, being made to the suction side of pump 16, and a furtherconnection 19, incorporating a valve 20, leadingfrom the delivery sideof pump 16 to the make-up tank.

Inserted in the line 13 are, as indicated, stop valves 14 and 15. Thesevalves are fully opened during the cycle of forwarding detergent liquidthrough line 13 but are closed when the pump 16 is used to forward theconcentrated liquid to the make-up tank 5, the valves 18 and 26 thenbeing opened. 7

When the stage is set for the cleaning operation, the valve 7 is open.

The return pump 21 is preferably arranged at a point in the circuitwhich requires a minimum amount of lift from the bottom of the oil tankor equivalent which is to be cleaned, and has its suction side connectedto lines 24 and 25. The first of these is connected to the sump (orlowest point of the oil tank being cleaned), thereby to ensure drainageof all the materials accumulated in the tank, and the second line 25represents a wandering suction line which is operated at any requiredpoint enabling certain of the contaminated detergent solution to bepicked up and returned to the scumming tank before reaching this lowestpoint, thus increasing the etliciency of the equipment in use.Preferably the line 25 is of. a flexible character, e. g. is a flexiblehose, so that it can quickly be located at any point in the interior ofthe tank or the like.

The lines 24 and 25 have stop cocks 24' and 25 therein which provide fortheir alternative use.

In some instances, such as modern cargo vessel tanks, there is a sump inthe bottom of the tank with a suction pipe passing laterally out of thesump. In such cases the return pump 21 is preferably arranged as near aspossible to the lowest level of the suction pipe from the sump, the line24 then being connected up to this suction pipe. In other cases the oiltank design or location may require that the lines 24 and/or 25 arepassed through the top of the tank to be cleaned.

In the case of double bottom tanks, with a central longiudinal bay andlongitudinal side bays, it is preferred to arrange the line 25 so thatit passes into the bottom of the side bay, the fixed line 24 beingconnected to the lowest fall of the tank bottom, such as the inboardlongitudinal.

Referring now to Figures 3 and 4 which show one form of the tank 1, itis to be noted that this comprises an outer casing 28 which is mountedon feet 29 whereby it can be arranged ill'flilYfiPPfOPIifil position, e.g-Jon the deck of a ship. The partition 2 constituting a heat insulatingdivision between the containers 3 and 4 is arranged so as to extendtransversely across the whole width of the tank but is spaced slightlyfrom the floor or bottom of the latter or is provided with anaperture(s) at its lower end so as to provide a communication orconnecting passage 32 between the two containers 3 and 4. This partitioncomprises a hollow casing forming an air space 31.

Alternatively, instead of a single tank 1 sub-divided into twocontainers, these containers may be separately formed and connected by apipe or pipes at their lower portions.

The scumming container 3 is initially filled with detergent liquid and,during the operation, serves the purpose of receiving heatedcontaminated detergent liquid, resulting from the cleaning of the oiltank or its equivalent, and permitting demulsification and gravityseparation of the detergent liquid from the oil carried thereby. Thedetergent liquid will be of greater specific gravity than the entrainedoil, so that the cleaned detergent liquid will separate out below theoil and pass through the passageway 32 beneath the baffle 2 into thedetergent container 4 for re-use. At the bottom part of the scummingcontainer 3 the floor or bottom of tank 1 is formed to provide hoppers33 adapted to receive solid matter separating from the liquid incontainer 3. Removal of this matter is effected, whenever required,through sludge valves 34.

Before passing to its place of use, the detergent liquid is heated and,in the example illustrated, the heating means, which is located in thedetergent container 4, consists of a coil 35, in which the arms arehorizontal and located one above the other, and which is supplied bysteam from the steam line 26 referred to in connection with Figure 1.The steam enters at 37 and passes out at 36 to a steam trap (not'shown).Alternatively an electric immersion heater may, for example, be used forthe same purpose.

The heated detergent liquid, for example at a temperature of 160 F.,passes out through an opening towards the upper end of the detergentcontainer 4 into the line 13 which is connected by a union 38 to thetank 1 at this point and includes a checking thermometer 145 in thevicinity of this union.

To make provision for reducing the temperature of the outgoingdetergentliquid if desired, cooler liquid, which has-not passed over the coil 35,can be admitted to line 13 via a branch 39 connecting with the bottom ofthe detergent container 4, by opening a valve 40 proportion of thedetergent liquid to flow to the pipe 13.

It isto be observed that the bafiie's 41and 42'extend the complete widthof the container. 7'

Also extending within the container 4 andabove' the coil 35, is a returnflow heating pipe 43, which is .of U- shape in plan and is connected bymeans of theunion 44, to the return line 22 indicated -in -Figure 1.This pipe 43 leads out again from the wall of the tank 1 and isconnected bya short section 45 to a tubular section 46 of enlargeddiameter in the scumming container 3. This section 46 terminates in a Tjunction 47 from which are branched two discharge pipes 48 which arehorizontally disposed, and located more or less diagonally in relationto the complete tank 1, in the upper portion of the scumming container3.

With a view to preventing turbulence the pipes 48 are open at theirupper parts for the majority of their lengths so as to form troughs 49from which the material returning from the cleaning operation outflowsto merge with the liquid in the scumming container 3. The pipes 48 aresupported at their free ends by brackets 50 arranged across theappropriate corners of the tank 1.

At the upper pan of one or both of the two side walls of the scummingcontainer 3 is arranged a slot 51 which communicates at the exterior ofthe container with a guide chute 52. This serves for discharge of thescum or oil, which separates out and rises to the upper region of theliquid in scumming container 3, to a sullage container or other meansfor the collection or conveyance away of the scum or oil. The container3, it will be understood, is always full of liquid up to the lower edgesof the slot or slots 51.

Arranged at a relatively short distance above the lower edge of thepartition 2, e. g. about one-fifth the distance from the tank floor orbottom 30 to the lower edge of overflow slot 51, is a float control forthe low level limit of the detergent liquid in the tank, this being inthe form of a valve 53 whose arm 54 is connected to a ball float 55which is so designed as to float on the detergent liquid but sink in theoil. The valve 53 is connected at 56 to the external make-up pipe 9leading to the make-up container 5 (see Figure 1), and the ball float isset so that, should the oil/ detergent liquid interface reach apredetermined low level limit, designated 146 in Figure 3 of thedrawings, the ball 55 will fall and cause the valve 53 to beautomatically opened to permit the passage of fresh detergent liquidfrom the make-up tank via the pipe 9, the valve 53, and a conduit 53from the valve 53, into the tank 1 in the vicinity of connecting passage32. The valve 53 automatically closes when the oil/detergent liquidinterface rises again above the lower level limit.

Also arranged in the scumming container 3 is a further float 57, againadapted to float on the detergent liquid but to sink in oil, this floatbeing adapted to operate any suitable indicator; for example it may becarried by a chain or cable which runs over a pulley 58 mounted on thetop of the tank 1 and which has at its other end an indicator 59co-operating with a scale 60 which'is suitably calibrated and is securedto the outside of the tank. The scale 60 and pulley 58 are shown, forconvenience of illustration, as attached to the left hand wall of thescumming container 3, but it will be understood that in practice theseparts would be secured to the far wall (as seen in Figure 3 of thedrawings) for convenience of inspection by the operator. The indicator59 thus indicates the level of the oil/detergent liquid interface in thecontainer 3 and, when this reaches a predetermined line below the slot51, e. g. 2 inches below the slot, as indicated at 146, the operatorwill adjust the valve 23 according to the tendency of the indicator torise above or fall below this working level line 146'. If this interfacelevel falls it will mean that the returning mixture of detergent liquidand contaminating matter has not a sufliciently high proportion ofdetergent solution in it to replace the controlled column of detergentliquid being discharged, as will hereinafter be described. The operatorwill then increase the rate of liquid return by operating valve 23,until the interface level is kept reasonably constant. If the indicatedinterface level tends to rise above 146' it means that the proportion ofdetergent liquid returning in the mixture is greater than is required tobalance the volume being discharged through line 13 so the operator willreduce the rate of return through valve 23.

Thus by keeping the interfacial level 146 reasonably constant, whateveroil is returned with the mixture separates out and forms a body of oilabove the interface level 146'. When such body of oil builds up to adepth of, say, 2" above the line 146 and its superficial surfacetherefore comes level with the slot 51, such superficial surface (oil ofhighest degree of reclamation) will start to overflow through slot 51.All succeeding re turned oil in the mixture returned through valve 23will similarly rise through the detergent liquid in the scummingcontainer 3 to lie on the superficial surface of the reclaimed detergentliquid at the maintained interfacial level 146 and thus force anautomatic proportional overfiow of reclaimed oil. through slot 51.

A further float-operated indicator 58, 59, 60 of similar form to thatdescribed above may be arranged on the auxiliary tank 5, as indicated inFigure l. The scale 60 is calibrated in inches and provides a means forgauging the dilution of the detergent liquid in the make-up tank to agiven percentage.

Operation of apparatus above described In operation, the tank 1 is firstfilled with detergent liquid and the steam heating coil 35 is broughtinto operation. The pumps 16 and 21 are then actuated so that heateddetergent liquid is drawn out through the line 13 and projected (as willbe later described) against the surfaces to be cleaned. The detergentliquid, carrying the oil and solids, is then returned via the valve 23,pipe 43 (where it is preheated to promote subsequent demulsification andseparation), and troughs 49 into the detergent liquid in the scummingcontainer 3. The oil then separates out from the detergent liquid bydemulsification and, owing to the greater density of the detergentliquid as compared with the oil, the oil forms in the upper region ofthe scumming container 3 on top of the detergent liquid. The separateddetergent liquid is continually drawn through the passage 32 for re-useso that it is recycled through the system and wastage avoided. The oilduly overflows through the slots 51 for collection and the solids settleto the bottom of the scumming container 3 whence they are periodicallyremoved through sludge valves 34.

Detergent liquid projecting means Various means which may be employedfor projecting the detergent liquid, passing through the line 13,against the surface to be cleaned are illustrated in Figures to 19.These means may be either mechanicallyor manually-operated.

Examples of the former are illustrated in Figures 5 to 12 in which theprojector for the detergent liquid comprises a series of pipes 61 whichmay be of any number and which are of diminishing diameter in theoutward direction of the projector and are arranged to telescope onewithin the other after the manner of a trombone. Each pipe has at itsforward end a gland comprising a gland nut 62, a packing ring 63 and agland neck bush 64, the next smaller trombone pipe in each case slidingwithin these parts with sufficient radial compression from the gland toprevent the escape of liquid.

Screw-threadedly attached to the rear end of each sliding trombone pipeis a piston head 65 having a central opening 66 therein which providesfor the passage of liquid into the pipe, this liquid initially enteringthe projector through a bore in an end nut 67 which is connected up tothe detergent liquid supply line 13. A longitudinal groove or channel 61is formed in each head 61 to relieve pressure in the space between itsskirt and the adjacent bush 64.

Connected by threading 68 (Figure to the front end of the foremosttrombone pipe 61, which is externally threaded for this purpose, is asleeve 69 which carries therein a short length of hollow shaft 70 whichis threaded at its rear end to a collar 71 adapted to bear against ashoulder formed in a socket provided at the inner end of this sleeve 69.At its front end the shaft 70 is screwthreaded, at 72, and engages withcorresponding internal threading in a boss 73 provided on the hub 74 ofa rotatable projector nozzle, being locked thereon by a nut 75..

In the example illustrated the projector nozzle has four radial arms,two of which, 76 and 77, represent nozzles for projecting the detergentliquid passing thereto from the trombone pipes, Whilst the other two, 78and 79, represent jet-reaction means for rotating these two nozzles. Itwill be observed from Figures 10 and 11 that the arms 78 and 79 arealigned with one another, but that the nozzles 76 and 77 have their axesparallel to each other but oblique to the axis of the shaft 70. Thispermits the projection of liquid to the desired places without unduestrain on the suspended projector.

The bores in the arms 76 and 77 are of tapered form and each includes,in its length, a tapered element 81 of cruciform shape, as seen fromFigure 12. This element serves to part the stream of liquid flowingthrough the bore of the respective arm into component streams whichconverge downstream from the element, this, coupled with the taperedform of the arm resulting in the liquid issuing from the nozzle as acompact stream.

Each of the arms 78 and 79 also has an internal passage, but of uniformcross section, which turns through a right angle short of the outer endof the respective arm so as to open from the latter at its rear. Thesetwo arms pass radially into the hub 74 and are/secured in the latter byscrew-threading and by lock nuts 82.

The detergent liquid flowing through the hollow shaft 70, when itreaches the boss 73, passes into the four arms. In the case of two ofthese, 78 and 79, it passes along the length of the arm and out throughthe orifice at the end thus, by jet reaction, causing the completenozzle unit to rotate. At the same time the liquid passes out from thearms 76 and 77 thus to be projected against the walls of the tank or thelike to be cleaned.

The apertures 66 in each of the piston heads are greater in area thanthe combined exit areas of the nozzles 76 and 77, whereby free passageof liquid can take place through the projector and maintain a pressureat these nozzles.

In use the detergent liquid is pumped into the projector at a suitablepressure, e. g. 80 to 100 pounds per square inch, and this causes theprojection of a stream of the detergent liquid from the nozzles 76 and77 against the surface to be cleaned. The rotation of the hub 73 by thejet-reaction arms 78 and 79 causes the liquid to sweep circumferentiallythe faces of the sides, bottom and top of the tank to be cleaned withsuccessive impingement on these parts of the detergent solution. T 0 prevent feathering and premature break-up of the issuing streams of liquid,the speed of revolution of the nozzle head is reduced by appropriaterotational setting of one or both of the arms 78 and 79 relatively tothe hub 74.

The projector may be operated from the outside of a tank 84 to becleaned (see Figure 6), by inserting the nozzle end through a hose 85 inthe wall or top of this tank, or alternatively the projector may bemounted inside the tank at any suitable point. Thus the projector can bemounted by a suitable hinging device such as is illustrated in Figure 6.In this case an arm 87 is connected by a lockable ball joint 87 topincers 86 rigidly secured to the rear trombone pipe 61. The other end87" of arm 87 is pivotally connected to a link 88 which has an abutmentstud 88 and is pivoted to a lug 89 mounted on a ring 90 which isrotatable within a flanged ring 91 secured around the opening 85. Theposition of the ring 90 can thus be varied rotationally, as desired and,having been adjusted, is secured in the selected position by screws 92,one of which is shown, having squared ends for operation by a wrench.The arm 87 co-operatcs with a scale 93 which forms part of the link 88,and the radial positioning of the projector from the horizontal status,through 90", to the vertical position is indicated by this and a furtherscale 94 secured to the projector.

By the means described the projector can be set to project streams ofliquid therefrom in any desired direction within the tank, thusproviding means whereby the streams of liquid from the nozzles 76 and 77can be projected against any corners or out-of-the-way parts, e. g.between roof trusses, of the internal surface of the tank to be cleaned.

Attached to the leading end of the first trombone pipe 61 isan eye bolt147 to which is attached a cable 148 by which, when the projector issuspended in the tank, this projector can be elevated to present thejets from the discharge nozzles at the appropriate striking anglerelatively to the tank structure. The free end of cable 14 is tied to acleat 149 on the plate 90.

It will furthermore be appreciated that the effective length of theprojector is also automatically variable, by virtue of the telescopicpipes 61 thereof and the fact that the entering detergent liquid exertspressure at the boss 73.

Thus, the nozzles are set to spray the tank walls starting with theprojector retracted and continuing until the latter is extended to itsfull length. Upon completion of this operation the projector isretracted and its direction re-set for extension in the new direction.By this means all areas within the tank can be reached by the streams ofdetergent solution, which are projected at a combined rate of, forinstance, 4 to 8 gallons per minute, so that the oil, asphalticresidues, and so on are broken down and detached from the metal walls bythe surface and interfacial tension reducing action of the detergentliquid and washed down to or towards the lowest point in the tank, beingpicked up and forwarded to the container 3 via the line 24 or 25 by thepump 21.

Restraining control for telescopic projecting means Figures to 9illustrate one form of means for mechanically controlling the speed ofthe extension of the trombone pipes 61. To this end there is providedaround the sleeve 69 a collar 95 of slightly greater diameter than thenut 67. Secured to this collar are the ends of a number of, for examplefive, rust-proof Bowden wires or nylon cables 96 which are spaceduniformly and radially around the collar 95. Each of these wires orcables 96 passes rearwards through corresponding guide orifices in acollar 97 adjacent the end nut 67, being guided in their passage betweencollars 95 and 97 by a series of appropriately perforated collars 98which are secured to the various trombone pipes 61 adjacent therespective gland nuts 62.

The wires or cables 96 pass rearwards from the projector through thewall of the tank being cleaned to a control mechanism which may, forexample, be mounted on the deck of the ship. This control mechanismcomprises a base 99 having an upstanding bracket 100 through which thewires or cables 96 pass at suitably spaced positions. Also mounted onthe base 99 are brackets 101 on which is rotatably mounted the shaft ofa drum 102. The wires or cables 96 pass round the outside of this drumand in turn around that of a further drum 103 spaced along the base 99from the drum 102. The drum 103 is loosely mounted on a transversemember 104 which has piston rods 105 projecting rearwards from each sideof the drum and carrying at their outer ends pistons 106 each arrangedin'a related cylinder 107. The ends of the member 104 are slidable inguideways 108 of channel section supported on the base 99.

The heads of the cylinders 107 above the heads of pistons 106 arerespectively connected by pipes 109 to a common conduit 110 whichcommunicates through a The amount of resistance to this extension iscontrolled by the amount of pressure fluid allowed to escape from theheads of the cylinders 107 through the pipes 109 and from the orificeplate controlled delivery pipe 110, this being determined bymanipulation of the bleed valve. When the automatic projector is to beshortened by telescoping the trombone pipes 61 one within the other,then the bleed valve is shut down to allow pressure to be exertedthrough the pipe 110, which causes the movement of the pistons 106 alongtheir cylinders 107, and, by virtue of the winding of the wires 96around the drums 102 and 103, a much magnified hauling in of these lines96 and thus quicker contraction of the length of the projector. Duringretraction a three-way cock (not shown) connected to t the line 13adjacent the nut 67 (Figure 6) is opened to relieve pressure on thetrombone pipes 61 by shutting 011 the supply of detergent liquid andopening the interior of these trombone pipes to atmosphere.

Manually operated projection means Preferably the equipment of theinvention also includes one or more manually operated projectors whichcan be used as an adjunct to or instead of the automatic projectorpreviously described, for example for dealing with small double-bottomtanks. A convenient form of such manually-operated projector isillustrated in Figures 13 to 16. This projector comprises a cylindricaltube 111 which is arranged for connection, e. g. by a union nut 112,with a hose line from the pump 16. Surrounding this tube is a handlegrip 113 which has hexagonal sides and which may conveniently be made ofa moulded plastic or of a material such as hard wood and which has aseries of circumferential grooves 114 to facilitate handling. The grip113 is secured on the tube 111' by washers 115 threaded on secured endsof the tube 111, and the latter carries at its outer end a T-junction116 providing a connection to a pair of branch nozzles 117 and 118.

These two nozzles are designed respectively to provide a long carryingjet with which the material to be cleaned olf the surface of the tank orthe like, is dealt with, and a wash down nozzle for washing the floor ofthe tank or the like. The two nozzles are independently controlled bymanually-operable cocks 119 and 120 respectively so that they can beused alternatively, as is the case in practice to avoid exaggeratedwithdrawal of detergent liquid from the scumming container 3, such aswould give insufiicient time for the desired separation therein.Alternatively the two nozzles may be controlled from a single multi-waycock.

The bore 121 through the nozzle 117 is, as shown by Figure 15, offrusto-conical section, tapering towards the outer end so as to projecta high velocity, and thus long-carrying, stream of detergent liquid tothe surface to be cleaned. There may, furthermore, be inserted in thisbore 121 an element 122 of cruciform shape in cross section and similarin form and function to the element 81 described in connection withFigures 10 to 12.

As shown by a comparison of Figures l3, l4 and 16 of the drawings, thenozzle 118 is of flattened fish tail form so that the jet of liquid fromthe bore 123 of this nozzle is of fiat'section. The sectional area ofthe jet emerging from the nozzle 118 is moreover larger than that of thejet from the nozzle 117, for example, twice the area.

The oil or the like detached from the walls of the apparatus beingcleaned by the action of the detergentliquid from the nozzle 117, andthen washed from the floor by the nozzle 118, is withdrawn by the returnpump 21 to the scumming container 3 for separation.

Modified projecting equipment for use, for example, with pistonsupercharger casings The apparatus illustrated in connection withFigures 17 to 19 is related to a form of projector, which may beincluded with the equipment according to the invention,

' for the removal "of certain kinds of oily deposits, such as the highlyoxidised oil in under piston supercharger casings, channels, etc., wheredischarge of a large body of water may not be practicable and where avery large concentration of the detergent, which term in this case mayinclude an appropriate solvent, needs to be applied to remove thesurface skin or varnish,- and also where leakage of foreign liquid outof the casing is undesirable, such as down the sides of a piston rodinto the crank case beneath, in the case of piston supercharger casings.

With this in view, the apparatus illustrated in Figures 17 to 19includes a collar 124 of resilient material, such as rubber, having abevelled lower surface 125 and, above this, a peripheral groove 126 forreceiving a tightening ring or spring 127. This collar is arrangedaround the piston rod 128 at a suitable distance beneath the piston 129and secured in position by tightening up the ring 127. To facilitatepositioning of the collar and this tightening operation, the collar 124is divided by a slot (not shown) which may be in the form of a diagonalscarf of such a width and formation that when the ring 127 is tighteningup the inner edges of the collar first contact one another before theside of the slot abut completely together.

When the collar 124 has been secured on the piston rod 128, the engineis turned to cause the rod to travel downwards until the collar has beentightly wedged in the opening 129 in the lower wall 130 of the underpiston chamber with its chamfered portion 125 sealing the opening 129.In this position the collar provides a complete water seal between theunder piston chamber and the crank case.

The projector used for supplying the detergent liquid and/or steam tothe cylinder walls in this case comprises a lance or nozzle 131 arrangedWithin a suction tube 132 which is connected by a coupling ring 151 tothe end of a lead from the return pump 21, e. g. the line 25. Secured tothe other end of the tube 132, by means of a band 133, is a suction hood134 of concertina-like form, and made of a flexible material, forexample rubber, which is impervious to the action of the steam(hereinafter referred to) and detergent used. As will be observed fromFigure 17, the tapered end 135 of the lance or nozzle 131 projects onlyslightly beyond the suction tube 132 so that this end 135 will, in use,be spaced from the cylinder wall 136, from which the deposit is to becleaned.

The lance or nozzle 131, at its rear end passes through the wall of thesuction tube 132, and is provided, outside tube 132, with an injectionunit comprising a casing 152 having an exit conduit 153 of which thelance 131 is a continuation. Opening into this conduit 153 is a branchconduit 157 connected to a lead 155 which is coupled to the supply line13 and, to the rear of the inlet into the conduit 153 of the conduit157, a further lead 154 from a pressure steam source. The steam thusacts in injector fashion and forwards the detergent liquid from the lead155 at high velocity into the lance 131. A valve 156 is provided inconduit 157 to control the inflow of detergent liquid or to enable it tobe shut off completely. The place 150 where the lance or nozzle 13].passes through the wall of tube 132 is suitably sealed.

The tube 132 will be inserted into the under piston chamber through theopening therein provided by removal of the outer casing and the end ofthe hood 134 pressed against the portion of the wall 136 or of thepiston or piston rod from which the deposit is to' be dislodged.

The steam and detergent liquid are then projected against the selectedwall portion. As the deposit accumulated in the supercharger underpiston chamber is practically insoluble when in the mass, the initialdislodgment of the deposit is effected by controlling the ratio of thevolume of detergent liquid to steam discharged, by operation of thevalve 156, thus causing projection of a concentrated jet of liquid athigh velocity on the mass, so causing the latter to break up and beloosened from the cylinder wall. Alternatively the ratio of liquid maybe smaller in comparison with the steam, merely wetting the skin orvarnish under low pressure.

A percentage of a solvent for the particular deposit may be added to thedetergent solution to encourage surface dissolution and break up of themass, and to remove the residual or inherent skin or varnish of:oxidised oil.

The initial break-down of the mass deposit may alternatively be achievedby cutting off the steam and projecting the detergent liquid only underpump pressure.

The deposit so dislodged is removed by suction through tube 132 to thescumming tank 3.

I claim:

1. A method of cleansing the interior surfaces of tanks by thesubstantial removal of oily deposits from such surfaces, such methodcomprising introducing at least one nozzle into the tank; heating andsupplying to the said nozzle an aqueous detergent liquid of suitableconcentration under such pressure that said liquid is projected againstand cleans the said surfaces; collecting the mixture of aqueousdetergent liquid and removed oily deposits; withdrawing said mixturefrom said tank; separating, by gravity separation, from such mixture theaqueous detergent liquid, the oil (which floats on the surface of theaqueous detergent liquid) and the sludge (which sinks in such liquid);withdrawing the said oil for reclamation; withdrawing the said sludgeseparately of said oil; reheating said separated aqueous detergcntliquid and recirculating it to said nozzle for further use.

2. A method of cleansing the interior surfaces of tanks by thesubstantial removal of water-insoluble deposits therefrom, such methodcomprising continuously (during the cleansing operation) heating andprojecting an aqueous detergent liquid against said surfaces whilstmoving the projected stream of liquid over such surfaces; continuouslycollecting and withdrawing from said tank the mixture of aqueousdetergent liquid and removed insoluble deposits produced by thecleansing operation; passing such withdrawn mixture in heat exchangerelationship with the said heated aqueous detergent liquid; continuouslyeffecting the gravity separation of such mixture into aqueous detergentliquid, a water-insoluble constituent which floats on the surface of theaqueous detergent liquid and water-insoluble sludge which sinks in theaqueous detergent liquid; withdrawing the said floating insolubleconstituent; withdrawing the said sludge; introducing into the liquidcycle fresh aqueous detergent liquid whenever the interface between theseparated floating insoluble constituent and aqueous detergent liquidfalls to a predetermined low level; re-heating said separated aqueousdetergent liquid and rte-projecting the same from said nozzle.

3. A method of cleansing the interior surfaces of tanks by thesubstantial removal of oily deposits therefrom, such method comprisingintroducing at least one nozzle into the tank; heating to about 160 F.and supplying to the said nozzle an aqueous detergent liquid comprisingan aqueous solution of a water-soluble alkaline compound or mixture inwhich the said compound or mixture incorporates up to 50% by weight of asynthetic wetting agent, said aqueous detergent liquid being supplied tothe said nozzle at a pressure of about to pounds per square inch at areturn of about 4 to 8 gallons per minute; projecting the said heatedaqueous detergent liquid against the surfaces to be cleansed; collectingthe mixture of said aqueous detergent liquid and the removed oilydeposits; withdrawing the said mixture from said tank; separating fromsuch mixture the aqueous detergent liquid, the oil and the heavier thanwater deposits; withdrawing the said oil; withdrawing the said heavierthan water deposits separately of the said oil; re-heating the saidseparated aqueous detergent liquid and re-circulating it to the saidnozzle for further use in the cleansing operation.

4. A method according to claim 3, in which the detergent of the saiddetergent liquid comprises 50 parts by 1 3 weight of sodiummetasilicate, 50 parts by Weight of anhydrcus sodium carbonate and 5 to15 parts of a Wetting agent of the sodium alkyl suiphate type.

Raferences Cited in the file of this patent UNTTED STATES PATENTS Re.19,374 Butterworth Nov. 20, 1934 1,142,083 Dodge June 8, 1915 1,487,062I-Iohl Mar. 18, 1924 1,492,956 Bots May 6, 1924 1,552,998 Menge Sept. 8,1925 1,557,240 Butterworth Oct. 13, 1925 1,628,141 Gray May 10, 1927Butterworth Dec. 4, 1928 McEwan June 18, 1929 Guardino July 23, 1929Butterworth May 26, 1931 FitzGerald Dec. 20, 1932 Meichers Sept. 1, 1936Waterman Mar. 18, 1941 Court Apr. 1, 1941 Van Gelderen July 20, 1943Brisse Nov. 14, 1950 FOREIGN PATENTS Great Britain Apr. 23, 1940 GreatBritain Jan. 21, 1949

1. A METHOD OF CLEANSING THE INTERIOR SURFACES OF TANKS BY THESUBSTANTIAL REMOVAL OF OILY DEPOSITS FROM SUCH SURFACES, SUCH METHODCOMPRISING INTRODUCING AT LEAST ONE NOZZLE INTO THE TANK, HEATING ANDSUPPLYING TO THE SAID NOZZLE AN AQUEOUS DETERGENT LIQUID OF SUITABLECONCENTRATION UNDER SUCH PRESSURE THAT SAID LIQUID IS PROJECTED AGAINSTAND CLEANS THE SAID SURFACES; COLLECTING THE MIXTURE OF AQUEOUSDETERGENT LIQUID AND REMOVED OILY DEPOSITS; WITHDRAWING SAID MIXTUREFROM SAID TANK; SEPARATING, BY GRAVITY SEPARATION FROM SUCH MIXTURE THEAQUEOUS DETERGENT LIQUID, THE OIL (WHICH FLOATS ON THE SURFACE OF THEAQUEOUS DETERGENT LIQUID) AND THE SLUDGE (WHICH SINKS IN SUCH LIQUID);WITHDRAWING THE SAID OIL FOR RECLAMATION; WITHDRAWING THE SAID SLUDGESEPARATELY OF SAID OIL; REHEATING SAID SEPARATED AQUEOUS DETERGENTLIQUID AND RECIRCULATING IT TO SAID NOZZLE FOR FURTHER USE.